Locking device



June 1s, 1940. E. s. cum/ER. 2,204,928

LOCKING DEVICE Filed May 31, 1958 y INVENTOR. idw/'f7 5. 'U/z/er ATTORNEY.

Patented June 18,

PATENT oFFlc LocmNG DEvIoE Edwin S. Culver, Oakland, Calif., assigno'r to Oliver United Filters Incorporated, San Francisco, Calif., a corporation of Nevada Application May 3l, 1938, Serial o. 210,849

5 claims. (Cl. 21o-199) l'I'his invention relates in general to a lockingn device for securing a piece of fabric. to a base member, and more particularly to a locking mechanism for securing a section of filter fabric toV 5 the division strips of a rotary drum iilter.

A rotary drum filter consists essentially of a pulp or slurry tank within which is rotatably disposed a drum formed on its outer surfacewith a plurality of adjacent independent filter cells dem fined by a plurality of spaced. longitudinally extending parallel division strips. 'I'he outer surfaces ofl the filter cells so formed are coveredv with a fabricated filter medium Awhich is secured to the drum by longitudinally extending grooves formed in th division strips. In thepast, various expedients have been resorted to for holding the fabric within the groovesof the division strips, such as by caulking, by screwing a solid strip of material within the groove of the division strip 2o and over the lterfabric, or by theuse of complementary wedge-shapedmembers as shown in the UnitedStates Duvall Patent No. 2,055,251' of September 22, 1936. Each of these expedients so resorted to is objectionable for some reason or other, as for example that the caulking works loose or that the lter fabric is not held with sum-- cient tension over the filter cells.

In general, the object of this invention is the provision of locking means for holding a piece oi' .fabric within a grooved base member in suchl a.

Way that the fabric may be tightly and smoothly hield in place and yet readily removed if so des red.

More specifically, the object of my invention is the provision .of a grooved base member formed with a restrictedthroat, in combination with a fflexible rubber tubing which may be disposed within said groove and. maintained in distended position so as to lock a section of filter. fabric within the groove.

The invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the following descriptionl where that form of the invention which has been selected for illustration in th drawing accom,- panying and forming a part of the-present specification is outlined in full. Insaid drawing, one form of the invention is shown, but it is to be understood that it is `not limited to such form, since the invention as set forth in the claims may be embodied in a plurality of forms.

Referring to the drawing:

Figure 1 is a fragmentary section of a rotary drum filter showing a grooved division strip formed with -a restricted throat.

Figure 2| shows the method of inserting a fold vof the lter medium within the grooved division stripshown in Figure l.

Figure 3 shows a method of inserting a piece of rubber tubing within a fold of the section of g filter medium disposed within the grooved divisin strip shown in Figure 1. l

Figure 1 is a fragmentary section of a rotary drum filter showing a section of filter fabric disl posed Within a grooved division strip and held in 1o place by a section of rubber tubing.

Figure 5 is a fragmentary section of a rotary drum filter showing the section of rubber tubing held in distended posi/tion by the insertion of a section of doweling. l5

The construction and operation of a continuous rotary drum filter need not here be described in` detail, for it is Well known to the trade and is fully disclosed inthe priorart such as the United States Akins Reissue Patent No. 14,214 20 oi? November 14, i916, and the United States Oliver .Patent No. 919,628 of April 27, 1909. Briefly, the essential elements of a filter of this type consists of a pulp or slurrytank within which is made to rotate a drum provided on its outer 25 surface with a plurality of longitudinally extending spaced division strips defining independent i'llter cells or compartments. y

As shown in the drawing, my invention has been embodied in a rotary drum filter of this 30 general type, comprising a drum I provided with a plurality of spaced lparallel longitudinally extending division strips 2. Each division strip is formed with a longitudinally extending groove 3 having a restricted throat l. The division 35 strips deiine independent filter cells or compartments 5 within which are disposed drainage members 6 for supporting a fabricated filter medium or cover 1 in spaced relation with respect to the drum.

As shown in Figure r2, a fold of the filter medium l is inserted into the longitudinally extending groove 3 by a wheel 8, and this having been done, a section of flexible rubber tubing 9 is forced into the groove 3 within the fold of the filter me- 45 dium. The resulting combination is shown in Figure 4 and from this ligure it is to be noted that the normal diameter .of the rubber tubing 9 lis greater than the throat 4 of the groove 3 but less than the greatest width of the groove.

' 50 l In order to lock the lter medium between the 7walls of the division strip and the section of rubbex` tubing, a section of doweling Il is then inserted within the rubber tubing as shown in msu-Te 5. 5

f medium is secured to each of the numerous divilL.; throat of saidgroove; a section'of fabric disposedin said groove between said base` member' sion strips of the drum in the same manner.

This method of locking the lter medium in place has various advantages over methods previously resorted to. En the first place, it will be noted that the rubber tubing @may be inserted within the groove 3 without moving the rubber tubing longitudinally with respect to the division strip, and therefore there is no tendency ior the lter medium to move longitudinally relative to the drum. and no tendency or it to wrinkle. Since the diameter of the rubber tubing Si is substantially less than that of the groove il, the d'oweling il may be inserted or stemmed through the rubber tubing without causing any relative motion between the rubber tubing and the division strip. The elimination of any relative motion between the rubber tubing and the division strip during the insertion oi' the doweling eliminates any corresponding relative movement between the lter medium and the division strip. Lastly. the filter medium may be readily disengaged from the drum lby first removing the doweling ii from the rubber tubing and then removing the rubber tubing from the groove 3. Although doweling has been used lfor holding the iiexible rubber tubing 8 in its distended position, obviously the same result can be eccomplished by inating the rubber tubing with air or by the insertion of'material other than doweling. i

While I have described my invention with particular reference to a continuous rotary drum filter of the tank type, it may if course be used for securing anymaterial of sheet form to any rrooved base member. s

I claim:

l. A clamp for locking fabric in place comprising: a base member: a groove in said member having a restricted throat; a section of hollow flexible tubing disposed in said groove, the normal diameter of said tubing being greater thanthe and said tubing; and means in addition to the escasas flexibility of said tubing for distending said tubing so as to lock said fabric within said groove.

2. A clamp for locking fabric in place comprising: a base member; a groove in said member having a restricted throat; a section of hollow flexible tubing disposed in said groove, the normal diameter of said tubing being greater than the throat of said groove; a section of fabric disposed in said groove between said base member and said tubing; and a solid member slidably disposed within 'said Jtubing for distending said tubing so as to'lock said fabric within said groove.

3. A clamp for locking fabric in place comprising: a base member formed with -a groove having a restricted throat; a section of hol1ow flexible tubing disposed within said groove, the normal diameter of said tubing being greater than the' restricted throat of said groove but somewhat less than the longest cross-sectional dimension of said groove; and means within said tubing for holding it in a distended position.

ll. A filter comprising: a base member formed with a groove having a restricted throat; a section of hollow exible tubing disposed within said groove, the normal diameter of said tubing being greater than the restricted throat of said groove; a section of fabric disposed in said groove between said base member and said tubing; and

means within said tubing for holding it in disf tended position so as to lock said fabric within said groove.

5. A filter comprsing: a rotary drum; a plurality of spaced division strips lsecured longitudinally of said drum and dividing said drum into a plurality of adjacent independent filter.'

cells; a longitudinally extending groove formed in one of said division strips. said groove having a restrictedthroat: a section of flexible tubing disposed within said groove, the normal diameter of said tubing being greater than said restricted throat; a section of fabric disposed in said groove between said division strip and said tubing: and means within said tubing for holding it in distended position so as to lock said fabric within said groove. l f

. EDWIN B. CULV'ER. 

